Spread The Pineapple Tidbits And Juice Evenly Over The Bottom Of A Slow Cooker. Stab The Pork Roast As Many Times As You Like With A Fork To Puncture So The Flavors Will Penetrate The Meat, Then Place Into The Slow Cooker. Pour The Rum Over Top, And Arrange The Orange Slices Around The Pork Roast. Place The Pineapple Rings On Top Of The Roast, And Place A Maraschino Cherry Into The Center Of Each Ring. Sprinkle With Brown Sugar. Set The Slow Cooker On Low, And Cook Until The Pork Is Fork Tender, 6 To 8 Hours. If Desired, Turn The Pork Over After 2 Hours, Then Again At The-5 Hour Mark.